Golang determine image dimensions.go

package main

import (
	"fmt"
	"strings"
	"strconv"
	"errors"
)

func determineImageDimensions(fileName string) (width, height uint64, err error) {

	sizeString, err := runProgram1("identify", "-format", "%[fx:w]x%[fx:h]", fmt.Sprintf("%v[0]", fileName))
	if err != nil {
		return 0, 0, err
	}

	sizeArr := strings.Split(sizeString, "x")

	if len(sizeArr) != 2 {
		return 0, 0, errors.New("Can't parse image dimensions")
	}

	width, err = strconv.ParseUint(sizeArr[0], 10, 64)
	if err != nil {
		return 0, 0, err
	}
	height, err = strconv.ParseUint(sizeArr[1], 10, 64)
	if err != nil {
		return width, 0, err
	}
	return
}